psss by value

pass by value: pass the copy value of the arguments feture: any change made to the parameter won’t affect the origin value

pass by reference: pass the reference of the arguments feature: any change made to the parameter will affect the orgin value

example:

1
2
3
4
5

def increse(number): # number= the copy of x
	number++

x=100
increae(x)

1
2
3
4
5
6
7
8
9

// num = the reference(pointer) of x
void increment(int& num) {
    num++;
}

int x = 5;
increment(x);
cout << x; // output: 6

problem: 为什么指针作为参数可以改变指针指向的值，却不是传递引用

1. 参数传递的还是指针的拷贝值
2. 对指针本身值的改变并不会影响外部指针的值
3. 混淆点: 并不是对指针本身的值改变，而是对指针指向值的改变